[Quest] Intruder Who Wants the Book of Giants - bug?

i play dwarf and now i have problem in this quest intruder who wants the book of giants . my level is 7 and i have only spoil and sweep as active skills. in part 3 in this q i must kill 2 thief in museum with my skills, normal attack do nothing.. now is not possible to kill this thiefs for me ?
anybody have idea?

 

you don't have to kill the thief with your skills.
you have to read the books in the library, check the books

 

ok, i must find the book, read it and die? because i can not kill thiefs?

 

read the book, read it, auto attack thiefs and exit zone

when they say you have to use your skills to kill the monsters, it's like "are you skilled enough to kill them ?"

 

just find the book, guard will kill them

 

intruder who wants the book of giants: i found the book, the text << use the skills......>> appeared, but not any progress.....